Cigarette inspection systems

ABSTRACT

A cigarette testing system includes a wrapper tester for detecting leaks in the wrappers of the cigarettes, means operated by the wrapper tester for ejecting faulty cigarettes, and means for testing the porosity of the web of wrapper material before it is formed into cigarette wrappers, the porosity tester comprising means for passing air through the wrapper web to generate a pressure signal dependent upon the degree of porosity of the wrapper material, and a pipe for conveying the pressure signal via a reservoir to the wrapper leak detector to provide compensation for the varying porosity of the wrapper material.

United States Patent 1191 Doerman 1 51 Jan. 9, 1973 s41 CIGARETTEINSPECTION SYSTEMS 3,111,026 11/1963 Powell ..73/38 Inventor: y StefanBowman London 2,952,262 9/1960 Pocock et al. ..13l/2l B gland PrimaryExaminer-Donald O. Woodiel [73] Assignee. Mohns Limited, London, EnglandAttorney craig Anmneni, Stewart & Hi" [22] Filed: Jan. 20, 1971 H N g[21] Appl. No.: 108,072 [57] ABSTRACT A cigarette testing systemincludes a wrapper tester [30] Foreign Application Priorit D t fordetecting leaks in the wrappers of the cigarettes, means operated by thewrapper tester for ejecting Feb. 27, 1970 Great Britain ..9,669/70faulty cigarettes, and means for testing the porosity of the web ofwrapper material before it is formed into [52] U.S. Cl. ..73/38cigarette wrappers, the porosity tester comprising [51] Int. Cl. ..G0lm3/00 means for passing air through the wrapper web to [58] Field ofSearch ..73/38, 40, 40.5 R, 45, 45.1, g n te a pressur ignal dependentupon the degree 73 452 37 37 21 3 of porosity of the wrapper material,and a pipe for conveying the pressure signal via a reservoir to the [56]Reterences Cited wrapper leak detector to provide compensation for thevarying porosity of the wrapper material.

18 Claims, 1 Drawing Figure CIGARETTE TNSPECTION SYSTEMS This inventionis concerned with cigarette testing systems in which the wrapper of eachcigarette is tested pneumatically for leaks. Any wrapper which allowsmore than a predetermined air flow through it is regarded as faulty andthe cigarette is ejected. The wrapper test may for example be asdescribed in U.S. Pat. No. 3,266,295.

Some cigarette wrappers are of a paper of which the porosity can varyconsiderably. At moments when the paper porosity is unusually high, theleak test of the cigarette wrapper tends to suggest a leaky wrapper eventhough the wrapper is in fact properly formed. On the other hand, wherethe paper porosity is exceptionally low, the air flow through thewrapper during the wrapper test could still be normal even though thewrapper has a definite hole or faulty seam. Accordingly it is desirableto test the porosity of the paper to obtain a porosity signal whichgoverns the level of air flow through the wrapper above which thewrapper should be regarded as unsatisfactory so as to warrant ejectionof the cigarette. One way of doing this is described in patentapplication Ser. No. 765,375, filed Oct. 7, 1968.

According to the present invention the porosity tester comprises a boxwhich is connected via a restrictor to a source of positive or negativepressure and has an opening across which the web of wrapper material isdrawn so that the inside of the box communicates with atmosphere throughthe part of the web closing off the opening. In addition there is a pipeleading from the box to transmit a variable pressure, depending upon thepaper porosity, to a pressure transducer or other device sensitive tothe variable pressure. It will be appreciated that the pressure in thebox at any moment depends upon the paper porosity; the greater theporosity, the lower will be the level of positive or negative pressurein the box.

An example of a suction system according to this invention is shown insolid lines in the accompanying diagrammatic drawing. lnthe drawing thecigarette wrapper tester is shown generally by the reference numeral 2.The principle is similar to that described in the above patent in thatsuction is connected at a testing station to a chamber 4 surroundingeach cigarette 5 in turn when it is at the testing station, and apressure signal is obtained from an end space defined by closure means 6enclosing one end of the cigarette,while the other end of the cigaretteis closed by closure means 7. It is important to note, however, that theclosure means 6 surrounds the cigarette end with a deliberate clearancegiving a leak to atmosphere and there may in addition be a furtherpredetermined leakage path to atmosphere, as described in patentapplication Ser. No. 795,279 filed Jan. 30, 1969, now US. Pat. No.3,608,380.

A suction source 8 is connected to the chamber 4 by a pipe 10 so as toestablish a suction pressure in the chamber 4 at a level of, forexample, 13 inches of water gauge. The suction source 8 is alsoconnected to a box 12 of a porosity testing device by means ofa pipe14including a restrictor 16. The box has a bleed 19 to atmosphere. Oneside of the box has an opening (or a number of openings) across which isdrawn a paper web 18 which is subsequently wrapped around a tobaccofiller to form a continuous cigarette rod, for example by means of acigarette making machine as described in British Pat. No. 916,141. Thecigarettes 5 are made by joining sections of this continuous rod toshort filter sections, and the completed cigarettes are then tested inthe wrapper tester 2. The web completely closes the opening or openingsin the side of the box, but its porosity allows air to flow through itand into the box, the amount of flow at any particular moment beingdependent on the degree of porosity of the paper.

The restrictor l6 and bleed 19 are preferably adjustable to enable thelevel of suction in the box to be readily varied. This facilitates thebalancing of the porosity signal with the wrapper test signal.

A pipe 20 leading from the box 12 connects the inside of the box to oneend of a pressure transducer 22 via a restrictor 24, a reservoir 26 anda restrictor 28; the restrictor 24 may be variable. This pressuretransducer 22 is also connected by a pipe 30 to the end space in theclosure means 6 of the wrapper tester; The transducer 22 includes adiaphragm 32 which is exposed to pressure in a space 34 and provides anelectrical output signal in accordance with the pressure in the space34. The pressure is determined mainly by the pressure signal from thewrapper tester via the pipe 30, but there is an additional compensatingsignal from the porosity tester. When the porosity of the paper iscomparatively'high, the suction pressure signal transmitted to thetransducer by the pipe 20 is comparatively low, so that the signal fromthe pipe .30 must be comparatively high before the output from thetransducer reaches the level at which cigarette ejection takes place. Onthe other hand, when the paper porosity is comparatively low, thesuction pressure signal transmitted to the transducer by the pipe 20 iscomparatively high, so a smaller signal from the pipe 30 will result inthe transducer receiving a net pressure such as to cause the cigaretteto be ejected.

In addition there is a suction pressure gauge 36 which gives a visualindication of the porosity pressure signal and facilitates theadjustment of the level of the mean porosity signal.

The reservoir 26 has the effect of providing a relatively long timeconstant. That is to say, it smooths out short-term variations in theporosity pressure signal. There may be a bleed to atmosphere from thereservoir, in which case the bleed 19 may be omitted.

As an alternative it is possible to use positive pressure in the box 12instead of negative pressure. For this purpose, the pipe 14 would bedisconnected from the suction source 8 and would be connected instead toa source of positive pressure 9, for example 13 inches of water gauge.The positive pressure signal transmitted from the box by the pipe 20would then not be connected to the same end of the transducer as thewrapper tester (i.e. to the pipe 30) but would instead be connected tothe opposite end of the pressure transducer, as shown by the dotted line37. In other words, from just upstream the restrictor 28 (or from justdownstream) there would be a pipe leading to the space in the transduceron the side of the diaphragm opposite to the space 34. This wouldprovide the same compensating effect as in the case of a negativepressure signal connected to the other end of the transducer, as shownin solid outlines.

In both the examples, the side of the box 12 along which the paper web18 is drawn may be convex instead of being straight as shown. This isespecially desirable in the case of positive pressure being used in thebox 12; the tension in the paper web in this case is needed to hold thepaper against the box and prevent the paper from being lifted from thebox by the air pressure in the box, the approaching and departinglengths of web being inclined to one another so that the web is partlywrapped round the box.

The pressure or suction signal from the porosity may be transmitted as aseries of pulses timed to coincide with the testing. of successivecigarettes (i.e. with the emission of suction pulses from the pipe 30).This is useful particularly if the electronics circuit coupled to thetransducer is an A.C. circuit. For example, the pipe transmitting theporosity pressure signal from the reservoir 26 may for example include arotary valve with porting such that its inlet and exit ports communicateand thus transmit the porosity pressure signal for a short period onceduring every revolution of the valve, the speed of the valve being Ntimes the speed of the fluted drum carrying the cigarettes during thewrapper test, where N equals the numberof flutes on the fluted drum.During the part of each revolution in which the valve is nottransmitting the porosity pressure signal through its exit port, thevalve preferably vents its exit port to atmosphere.

What i claim as my invention and desire to secure by Letters Patentis:

l. A cigarette testing system including a wrapper tester for detectingleaks in the wrappers of the cigarettes, means operated by the wrappertester for ejecting faulty cigarettes, and means for testing theporosity of the web of wrapper material before it is formed intocigarette wrappers, the porosity tester comprising means for passing airthrough the wrapper web to generate a pressure signal dependent upon thedegree of porosity of the wrapper material, and a pipe for conveying thepressure signal via a reservoir to the wrapper leak detector to providecompensation for the varying porosity of the wrapper material.

2.. A testing system according to claim 1 in which the wrapper testerincludes a diaphragm transducer which is fed with a pressure signal froma pneumatic wrapper testing device and which produces an electricaloutput signal indicative of the air flow through the wrapper of eachcigarette, the pressure signal generated by the porosity tester beingfed also to the diaphragm transducer so as to apply a bias reinforcingthe wrapper test signal.

3. A testing system according to claim 2 in which the wrapper testsignal and porosity signal are of opposite senses and are applied toopposite sides of the diaphragm of the transducer.

4. A testing system according to claim 3 in which the wrapper testsignal is a negative pressure signal while the porosity signal is apositive pressure signal.

5. A testing system according to claim 1 in which the pressuresignalfrom the porosity tester is fed to the wrapper tester as a seriesof pulses timed to coincide withthe testing of successive cigarettes bythe wrapper tester.

6. A testing system according to claim 1 in which the porosity testercomprises a box which is connected via a restrictor to a source ofpositive or negative pressure and has an opening across which the web ofwrapper material is drawn, so that air flows between the atmosphere andthe inside of the box through the part of the web which lies across theopening.

7. A testing system according to claim 6 in which the box includes avent to atmosphere.

8. A testing system according to claim 7 in'which the vent is adjustableto vary the mean stretch of the porosity signal.

9. A cigarette, testing system including a wrapper tester for detectingleaks in the wrappers of the cigarettes, means operated by the wrappertester for ejecting faulty cigarettes, and means for testing theporosity of the web of wrapper material before it is formed intocigarette wrappers, the porosity tester comprising a box which isconnected via a restrictor to a source of positive or negative pressure,means defining an opening across which the web of wrapper material isdrawn, so that air flows between the atmosphere and the inside of thebox through the part of the web which lies across the opening and thusproduces a variable pressure in the box dependent upon the porosity ofthe web, and pipe means for convening this variable pressure as aporosity signal to the wrapper tester to provide compensation at thewrapper tester for the varying porosity of the wrapper material.

10. A testing system according to claim 9 in which the box includes avent to atmosphere.

11. A testing system according to claim 10 in which the vent isadjustable to vary the mean strength of the porosity signal.

12. A testing system according to claim 9 in which the wrapper testerincludes a diaphragm transducer which is fed with a pressure signal froma pneumatic wrapper testing device and which produces an electricaloutput signal indicative of the air flow through the wrapper of eachcigarette, the pressure signal generated by the porosity tester beingfed also to the diaphragm transducer so as to apply a bias reinforcingthe wrapper test signal.

13. A testing system according to claim 9 in which the wrapper testsignal and porosity signal are of opposite senses and are applied toopposite sides of the diaphragm. of the transducer.

14. A cigarette testing system comprising a wrapper tester for detectingleaks -in the wrapper of the cigarettes and including a pneumaticwrapper testing device which feeds test pressure signals to one side ofthe diaphragm of a diaphragm transducer which produces an electricaloutput signal indicative of the air flow through the wrapper of eachcigarette, and a porosity tester comprising means for passing airthrough the wrapper web before it is formed into cigarettes to generatea porosity pressure signal dependent upon the degree of porosity of thewrapper material, the porosity pressure signal being of opposite senseto the test pressure signals produced by the pneumatic wrapperv testingdevice, and including means for feeding said porosity pressure signaland test pressure signals to opposite sides of the diaphragm of thetrans ducer. v

15. A testing system according to claim 14 in which the wrapper testsignal is a negative pressure signal while the porosity signal is apositivepressure signal.

16. A cigarette testing system including a wrapper tester for detectingleaks in the wrappers of successive cigarettes and for producing apressure signal indicative of the air flow through each cigarettewrapper in turn, and means for testing the porosity of the web ofwrapper material before it is formed into cigarette wrappers, theporosity tester comprising means for passing air through the wrapper webto generate a pressure signal dependent upon the degree of porosity ofthe wrapper material, and means for conveying this pressure signal as aseries of timed pulses to the wrapper tester to provide compensation forthe varying porosity of the wrapper material, the timing of these pulsesbeing arranged to coincide with the testing of successive cigarettes bythe wrapper tester.

17. A method of testing cigarettes comprising pneumatically testing thewrapper of each cigarette to produce a first pneumatic test signal,feeding the first test signal to a diaphragm transducer giving anelectrical output signal, pneumatically testing the porosity of the webof material used to form the wrappers of the cigarettes before beingused to form the cigarette wrappers to produce a second pneumatic testsignal, and feeding the second pneumatic test signal to the diaphragmtransducer so as to apply a bias reinforcing the first signal to adegree dependent upon the porosity of the web.

18. A method of testing cigarettes formed from a tobacco rod wrapped ina continuous web of wrapping material, comprising continuously testingthe porosity of the web of wrapping material before it is formed intothe rod wrapper, testing the cigarettes for air leaks in their wrappers,rejecting unsatisfactory cigarettes according to the results of suchwrapper testing, and controlling the sensitivity of said cigarettewrapper testing in accordance with the results of said porosity test ofsaid web of wrapping material.

1. A cigarette testing system including a wrapper tester for detectingleaks in the wrappers of the cigarettes, means operated by the wrappertester for ejecting faulty cigarettes, and means for testing theporosity of the web of wrapper material before it is formed intocigarette wrappers, the porosity tester comprising means for passing airthrough the wrapper web to generate a pressure signal dependent upon thedegree of porosity of the wrapper material, and a pipe for conveying thepressure signal via a reservoir to the wrapper leak detector to providecompensation for the varying porosity of the wrapper material.
 2. Atesting system according to claim 1 in which the wrapper tester includesa diaphragm transducer which is fed with a pressure signal from apneumatic wrapper testing device and which produces an electrical outputsignal indicative of the air flow through the wrapper of each cigarette,the pressure signal generated by the porosity tester being fed also tothe diaphragm transducer so as to apply a bias reinforcing the wrappertest signal.
 3. A testing system according to claim 2 in which thewrapper test signal and porosity signal are of opposite senses and areapplied to opposite sides of the diaphragm of the transducer.
 4. Atesting system according to claim 3 in which the wrapper test signal isa negative pressure signal while the porosity signal is a positivepressure signal.
 5. A testing system according to claim 1 in which thepressure signal from the porosity tester is fed to the wrapper tester asa series of pulses timed to coincide with the testing of successivecigarettes by the wrapper tester.
 6. A testing system according to claim1 in which the porosity tester comprises a box which is connected via arestrictor to a source of positive or negative pressure and has anopening across which the web of wrapper material is drawn, so that airflows between the atmosphere and the inside of the box through the partof the web which lies across the opening.
 7. A testing system accordingto claim 6 in which the box includes a vent to atmosphere.
 8. A testingsystem according to claim 7 in which the vent is adjustable to vary themean stretch of the porosity signal.
 9. A cigarette testing systemincluding a wrapper tester for detecting leaks in the wrappers of thecigarettes, means operated by the wrapper tester for ejecting faultycigarettes, and means for testing the porosity of the web of wrappermaterial before it is formed into cigarette wrappers, the porositytester comprising a box which is connected via a restrictor to a sourceof positive or negative pressure, means defining an opening across whichthe web of wrapper material is drawn, so that air flows between theatmosphere and the inside of the box through the part of the web whichlies across the opening and thus produces a variable pressure in the boxdependent upon the porosity of the web, and pipe means for conveningthis variable pressure as a porosity signal to the wrapper tester toprovide compensation at the wrapper tester for the varying porosity ofthe wrapper material.
 10. A testing system according to claim 9 in whichthe box includes a vent to atmosphere.
 11. A testing system according toclaim 10 in which the vent is adjustable to vary the mean strength ofthe porosity signal.
 12. A testing system according to claim 9 in whichthe wrapper tester includes a diaphragm transducer which is fed with apressure signal from a pneumatic wrapper testing device and whichproduces an electrical output signal indicative of the air flow throughthe wrapper of each cigarette, the pressure signal generated by theporosity tester being fed also to the diaphragm transducer so as toapply a bias reinforcing the wrapper test signal.
 13. A testing systemaccording to claim 9 in which the wrapper test signal and porositysignal are of opposite senses and are applied to opposite sides of thediaphragm of the transducer.
 14. A cigarette testing system comprising awrapper tester for detecting leaks in the wrapper of the cigarettes andincluding a pneumatic wrapper testing device which feeds test pressuresignals to one side of the diaphragm of a diaphragm transducer whichproduces an electrical output signal indicative of the air flow throughthe wrapper of each cigarette, and a porosity tester comprising meansfor passing air through the wrapper web before it is formed intocigarettes to generate a porosity pressure signal dependent upon thedegree of porosity of the wrapper material, the porosity pressure signalbeing of opposite sense to the test pressure signals produced by thepneumatic wrapper testing device, and including means for feeding saidporosity pressure signal and test pressure signals to opposite sides ofthe diaphragm of the transducer.
 15. A testing system according to claim14 in which the wrapper test signal is a negative pressure signal whilethe porosity signal is a positive pressure signal.
 16. A cigarettetesting system including a wrapper tester for detecting leaks in thewrappers of successive cigarettes and for producing a pressure signalindicative of the air flow through each cigarette wrapper in turn, andmeans for testing the porosity of the web of wrapper material before itis formed into cigarette wrappers, the porosity tester comprising meansfor passing air through the wrapper web to generate a pressure signaldependent upon the degree of porosity of the wrapper material, and meansfor conveying this pressure signal as a series of timed pulses to thewrapper tester to provide compensation for the varying porosity of thewrapper material, the timing of these pulses being arranged to coincidewith the testing of successive cigarettes by the wrapper tester.
 17. Amethod of testing cigarettes comprising pneumatically testing thewrapper of each cigarette to produce a first pneumatic test signal,feeding the first test signal to a diaphragm transducer giving anelectrical output signal, pneumatically testing the porosity of the webof material used to form the wrappers of the cigarettes before beingused to form the cigarette wrappers to produce a second pneumatic testsignal, and feeding the second pneumatic test signal to the diaphragmtransducer so as to apply a bias reinforcing the first signal to adegree dependent upon the porosity of the web.
 18. A method of testingcigarettes formed from a tobacco rod wrapped in a continuous web ofwrapping material, comprising continuously testing the porosity of theweb of wrapping material before it is formed into the rod wrapper,testing the cigarettes for air leaks in their wrappers, rejectingunsatisfactory cigarettes according to the results of such wrappertesting, and controlling the sensitivity of said cigarette wrappertesting in accordance with the results of said porosity test of said webof wrapping material.